Under a settlement with regulators, the company must revamp some operations before resuming sales of its CPAP and ventilator devices in the United States.Philips Respironics announced on Monday that it would halt sales of all of its breathing machines in the United States after reaching a settlement with the Food and Drug Administration over continuing problems with the devices.Millions of the company’s ventilators and CPAP machines, used to ease breathing at night, were recalled after reports that they blew bits of foam and potentially toxic gases into consumers’ airways.Under the settlement, Philips said it would have to meet a list of standards in a “multiyear” plan before it could resume business in the United States. The company said further details would be disclosed when the agreement was finalized in court. But it added that it would continue to repair existing devices and provide service for people using them.The company initially began the recall of millions of devices in June 2021 and paused sales of new sleep therapy machines to the United States, according to Steve Klink, a spokesman for Philips. At the time, the company and the F.D.A. cited the potential for serious injury or permanent impairment from the potentially cancer-causing chemicals emitted from the devices.The company has since released results of additional testing, saying the devices were “not expected to result in appreciable harm to health in patients,” and it said it was continuing to conduct tests. The F.D.A. has pushed back on some of the company’s updated claims, and at one point called them “unpersuasive.” Philips has also faced continuing scrutiny and undertaken more recalls in its attempts to upgrade the devices.Dr. Jeff Shuren, director of the F.D.A.’s device division, said the agency could not comment until the agreement was finalized and filed with the court.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? 

The agency has reviewed reports of cancer patients whose treatments resulted in the development of secondary blood cancers. Several companies will be required to carry the new warning.The Food and Drug Administration is requiring companies that make specialized cancer therapies known as CAR-T to add a boxed warning that the treatments themselves may cause cancers.The agency noted that the benefits still outweighed the risks of the therapy, which involves removing a type of white blood cells — T cells — and then genetically engineering them to create proteins called chimeric antigen receptors (CAR). Infused back into a patient’s blood, the engineered cells allow the T cells to attach to cancer cells and kill them.But the therapies, which mostly treat blood cancers, including multiple myeloma, had already carried a warning for dangerous immune responses and for neurological risks. And the new warning follows reports of about 20 cases of secondary cancers that federal health officials and others have suspected were caused by CAR-T treatments, although more investigation may be needed to establish a definite link. The therapy has been used by an estimated 25,000 to 30,000 patients since it was first approved by the F.D.A. in 2017.Cancer patients who receive CAR-T treatments tend to have few options left, and would be unlikely to alter course even with the new warning, said Dr. John DiPersio, an oncologist with Washington University in St. Louis.“The risk of not doing this therapy for most patients who get it is rapid progression of their disease or certain death,” he said.The F.D.A. raised concerns about the adverse effects of the treatments late last year.In letters dated Jan. 19, the agency outlined the warnings to be included by some of the companies making CAR-T therapies, which had also been ordered to monitor patients for secondary cancers and report any to the F.D.A. The secondary cancers can lead to hospitalizations or death, the agency noted, requiring the drug companies to provide warnings on drug labels that secondary cancers “may present as soon as weeks following infusion, and may include fatal outcomes.”We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? 

With Covid deaths rising to about 1,500 per week, researchers question why Paxlovid use has remained low among high-risk patients.As Covid rises again, killing about 1,500 Americans each week, medical researchers are trying to understand why so few people are taking Paxlovid, a medicine that is stunningly effective in preventing severe illness and death from the disease.A study of a million high-risk people with Covid found that only about 15 percent who were eligible for the drug took it. If half of the eligible patients had gotten Paxlovid, 48,000 deaths could have been prevented, authors of the study, conducted by the National Institutes of Health, concluded.It’s not because people don’t know about the drug — most do — but the reluctance seems to come from doctors worried about interactions with other drugs and people wary of a possible rebound case or the metallic aftertaste.Regional differences offer a clue, with uptake highest in the Democratic strongholds of the Northeast and Pacific Northwest regions of the United States and lowest in deep red areas including Florida and Indiana. Yet no careful study has clarified why so few people used the medication, which cut the risk of death by 73 percent for high-risk patients in the N.I.H. study.“I don’t know why there is such variability and why uptake isn’t higher across the board,” said Dr. Josh Fessel, a senior clinical adviser on the National Institutes of Health team that studied the drug’s use. “If you can take Paxlovid and you do take Paxlovid within the recommended time frame, the likelihood of death or hospitalization are significantly reduced. That’s a big deal.”Covid deaths have been elevated since September at about 1,200 to 1,300 deaths per week, inching up to about 1,500 per week in December. Researchers say they will most likely continue to rise unless more people get the updated Covid vaccines and antiviral treatments.Dr. Fessel said that over the course of the entire million-person N.I.H. study, about 10 percent of high-risk patients eligible for Paxlovid took it, though the rate rose to about 15 percent toward the end of the study period in early 2023. All told, the N.I.H. authors estimated that about 135,000 hospitalizations and 48,000 deaths could have been avoided if half of the patients eligible for the antiviral got it.Paxlovid, made by Pfizer, is a two-medication treatment meant to be taken within five days of the onset of Covid symptoms to quash viral spread within the body. It was approved for adults who are at high risk for severe Covid, which tends to include those 65 and older and people with diabetes, obesity, asthma and other conditions.Federal officials still have more than one million free doses out to pharmacies, but officials have handed distribution of the drug off to Pfizer, which has priced it at $1,400 per course.Pfizer, via ReutersReasons for not prescribing or taking it have varied: Doctors balk at the long list of medications not to be mixed with Paxlovid, including common drugs meant to lower blood pressure or prevent blood clots. Patients tend to complain about the drug’s metallic aftertaste. Many wave off the drug in the early days of Covid, when symptoms tend to be mildest, bypassing the chance to limit early viral growth.“They want to wait and see if things get worse, but if you wait and see it’s not effective,” said Dr. David Gifford, chief medical officer of the American Health Care Association, which represents nursing homes. People think, “‘It’s just a cold and I’ll tough it out,’” he said. “And that needs to change.”Price has also become a factor. The federal government provided the five-day course of the medications at no cost in the months since its initial emergency authorization in December 2021. (The Food and Drug Administration fully approved the drug in May.) Federal officials still have more than one million free doses out to pharmacies, and the medication will be free through 2024 for Medicaid and Medicare patients. But in recent weeks, officials have handed distribution of the drug off to Pfizer, which has priced it at about $1,400 per course, though private insurers are expected to cover some portion of the price and Pfizer is offering co-payment assistance.No study has looked at the effect of the handoff. The N.I.H. study period ended early last year. It found wide regional variation in Paxlovid use, with as many as 50 percent of eligible patients getting the medication in Utah and in the Northeast and Northwest regions of the United States. However, rates dipped close to zero in states in the Southeast and in parts of the lower Midwest.Dr. Fessel, of the N.I.H., said he would be curious to see if concerns about so-called Paxlovid rebound contributed. The misgiving has been that the medication dampens symptoms initially and then leads to a second stage of illness.In a recent review of studies, the Centers for Disease Control and Prevention found “no consistent association” with Paxlovid use and Covid rebound. Studies show rebound can also happen without treatment.Denis Nash, a professor of epidemiology at the City University of New York, has also been studying Paxlovid use. In a far smaller study, his team also found uptake of the medication at nearly 14 percent, though lower among some, including 7 percent among people who are Black and nearly 11 percent among those with the lowest income levels.He said his team worked on a nationally representative survey of 4,000 people to dig deeper (results have not yet been published or peer reviewed). One interesting finding, he said, was that awareness of Paxlovid was high — with about 80 percent of respondents saying they knew that it was available.Yet respondents showed a lack of recognition about their own risk: Only about one-third of people older than 65 considered themselves to be at high risk for severe Covid, even though the C.D.C. considers all in that age group high risk. The finding was similar for patients with asthma or diabetes, though half of patients who were overweight or obese recognized their risk.“People don’t necessarily perceive themselves to be at risk,” Dr. Nash said.Another recent study found that starting Paxlovid very early, or on the first day of symptoms, improved odds of survival or avoiding hospitalization, compared with starting the drug a day or two later.Studies have also looked at the use of another antiviral drug, molnupiravir, made by Merck, which was less effective and is used less frequently. Gilead, which makes the antiviral infusion remdesivir, is also studying a Covid antiviral pill called obeldesivir and plans to seek F.D.A. approval. The N.I.H. is studying yet another antiviral option, ensitrelvir, by the company Shinogi that also appears to reduce duration of the illness.Researchers have also reported low Paxlovid use in nursing homes, given the risk patients face of serious illness or death. About one in four nursing home residents got an antiviral prescription to treat Covid by the end of 2022, a study found. The data showed that the rate rose to closer to one-third of nursing home residents by May 2023, said one study author, Brian McGarry, a University of Rochester assistant professor of medicine.After that, federal officials stopped asking about Paxlovid use in their weekly nursing home Covid questionnaire.“I think things are a little bit better,” Dr. McGarry said, “but at the same time, facilities are now dealing with Covid, plus R.S.V., plus flu.”

Key drugs have been in scarce supply, revealing a deep crisis in the generic drug industry.Stephanie Scanlan learned about the shortages of basic chemotherapy drugs this spring in the most frightening way. Two of the three drugs typically used to treat her rare bone cancer were too scarce. She would have to go forward without them.Ms. Scanlan, 56, the manager of a busy state office in Tallahassee, Fla., had sought the drugs for months as the cancer spread from her wrist to her rib to her spine. By summer it was clear that her left wrist and hand would need to be amputated.“I’m scared to death,” she said as she faced the surgery. “This is America. Why are we having to choose who we save?”The disruption this year in supplies of key chemotherapy drugs has realized the worst fears of patients — and of the broader health system — because some people with aggressive cancers have been unable to get the treatment they need.Those medications and hundreds of other generic drugs, including amoxicillin to treat infections and fentanyl to quell pain during surgery, remain in short supply. But the deepening crisis has not fostered solutions to improve the delivery of generic drugs, which make up 90 percent of prescriptions in the United States.Dr. Robert Califf, commissioner of the Food and Drug Administration, has outlined changes the agency could make to improve the situation. But he said the root of the problem “is due to economic factors that we don’t control.”“They’re beyond the remit of the F.D.A.,” he said.Senator Ron Wyden, a Democrat of Oregon and chairman of the Senate Finance Committee, agreed. “A substantial portion of these market failures are driven by the consolidation of generic drug purchasing among a small group of very powerful health care middlemen,” he said at a hearing this month.In interviews, more than a dozen current and former executives affiliated with the generic drug industry described many risks that discourage a company from increasing production that might ease the shortages.They said prices were pushed so low that making lifesaving medicines could result in bankruptcy. It’s a system in which more than 200 generic drugmakers compete, at times fiercely, for contracts with three middleman companies that guard the door to a vast number of customers.In some cases, generic drugmakers offer rock-bottom prices to edge out rivals for coveted deals. In other instances, the intermediaries — called group-purchasing organizations — demand lower prices days after signing a contract with a drugmaker.The downward pressure on prices — no doubt often a boon to the pocketbooks of patients and taxpayers — is intense. The group purchasers compete against one another to offer hospitals the lowest-priced products, which intermediary companies say also benefits consumers. They earn fees from drugmakers based on the amount of medications the hospitals buy.“The business model is broken,” said George Zorich, a pharmacist and retired generic drug industry executive. “It’s great for G.P.O.s. Not great for drug manufacturers, not great for patients in some cases.”Ms. Scanlan’s cancer was deemed curable for about 65 percent of patients after cisplatin was added to the cocktail. But during her treatment, Ms. Scanlan got only one dose of a sister drug, carboplatin.Emil Lippe for The New York TimesMany doctors wish they could do more to give cancer patients the medicines they need.“Every clinician I know would be thrilled to pay more money for a reliable supply of a quality drug,” said Dr. Andrew Shuman, a University of Michigan oncology surgeon and expert on drug shortages.In a speech to drug supply intermediaries last month, Dr. Califf exhorted them to “pay more,” saying it would enhance access to medical products and would be “good for business.”Prices fell in recent years for two of the three drugs that Ms. Scanlan was initially offered to treat her cancer. During those years, Intas Pharmaceuticals, a generics giant in India, steadily gained market share as other companies left, according to data from the U.S. Pharmacopeia, a nonprofit that tracks drug shortages.But the company had to halt U.S. production to deal with quality issues that the F.D.A. cited after a surprise inspection of one of its sprawling plants in India. Inspectors had discovered quality-control staff workers shredding and throwing acid on key records. The manufacturing shutdown set off a supply shock in February that would be felt nationwide.Nearly every major U.S. cancer center reported in surveys that they faced chemotherapy shortfalls last spring and summer. One survey released in August found that nearly 60 percent of more than 1,000 pharmacy respondents deemed chemotherapy drug shortages “critically impactful.”Intas recently resumed production, but the F.D.A. still lists the drugs as being in short supply. Major cancer centers report that the shortages are easing, though concerns persist about stock in rural areas.The scarce drugs are cheap and essential and revolutionized their field decades ago, for the first time curing some patients with testicular, lung, ovarian, pancreatic and breast cancers, oncologists say.Ms. Scanlan’s cancer, called osteosarcoma, was deemed curable for about 65 percent of patients after cisplatin was added to the cocktail regimen in the 1970s.Ms. Scanlan’s medical records outline her care. For treatment in the spring and summer, she received only one infusion in March of a sister drug, carboplatin, at University of Florida Shands Hospital in Gainesville.As months passed, Ms. Scanlan’s cancer spread deeper into her bones. She was referred to Tallahassee Memorial Hospital, which, because of the shortages, treated her with one chemotherapy drug. The center then referred Ms. Scanlan to the Mayo Clinic site in Jacksonville in April, according to her medical records.Ms. Scanlan, with her dog, Rosie. “This is America,” Ms. Scanlan said. “Why are we having to choose who we save?”Mark Wallheiser for The New York TimesYet even at the gleaming Florida outpost of the elite medical system, Ms. Scanlan could not get her chemo treatments.By May, she was facing surgery, but might have been eligible to have her wrist repaired rather than amputated. Notes in her records by her Mayo oncology surgeon, Dr. Courtney Sherman, said it would depend on how Ms. Scanlan responded to treatment, though “she is not receiving standard chemotherapy given shortages.”In May and June, both Ms. Scanlan and Dr. Sherman pressed Dr. Steven Attia, a Mayo oncologist, to order the infusions. Ms. Scanlan emailed Dr. Attia: “One question, does Mayo not have the chemo that I actually need?”Dr. Attia declined requests for comment. Samiha Khanna, a Mayo spokeswoman, denied that its site in Jacksonville experienced a cancer drug shortage and confirmed that Mayo did not administer chemotherapy to Ms. Scanlan. Ms. Khanna also referred questions back to Tallahassee Memorial.A market transformedOver the course of his career in the generic drug field, Jeff Herzfeld, a pharmacist and former generics executive who works as a consultant, watched it morph from a field with modest profits to one that is cutthroat.At first it seemed no one was going to make high profits in the generic industry. As drug patents expired, companies entered the market and won customers by offering low prices.But the field of customers began to shrink about 15 years ago. Intermediary companies realized that they could organize hospitals to wield their mass-buying power to get even lower prices.Those intermediaries, or G.P.O.s, charged fees to drugmakers that could access a vast swath of customers. The G.P.O.s competed with one another for hospital clients — enticing them with the lowest prices.The competition stiffened as generic drugmakers vied for each huge deal, emerging victorious if they came in with the lowest price. “They had a winner-take-all approach,” Dr. Herzfeld said.Big deals also came with tough contract terms. One allowed the G.P.O.s to return to the generic drugmaker days after a deal with an ultimatum: Lower the price more or lose the contract. It could happen repeatedly. “You don’t have a lot of room for error,” Dr. Herzfeld said.Generic drug executives said common contract terms deterred them from helping out in a shortage. If they fail to supply promised medications, they can face hefty fines. Yet if they produce more drugs than hospitals buy, they are left with a hole in their balance sheet.Intas Pharmaceuticals, a generics giant in India, steadily gained market share as other companies left the market.Sam Panthaky/Agence France-Presse — Getty ImagesThese routine contract clauses “really penalize or punish” generic drugmakers, said David Gaugh of the Association for Accessible Medicines, which represents the generics industry.Todd Ebert, president of the Healthcare Supply Chain Association, which represents G.P.O.s, disputed those views, arguing that some generic drugmakers offered very low “predatory” prices to force competitors out of the business.Without knowing the cost of producing the drugs, companies cannot be certain if a price is a bargain — or a tactic to hobble the competition, he said. Vizient, a major group purchaser, referred comment to Mr. Ebert.Jessica Daley, a supply chain vice president with Premier, a leading drug-purchasing company, said the company strove to foster healthy markets and wanted “reasonable prices that support supply resiliency and protect patient care.”Aside from the group purchasers’ terms, generic drugmakers also point to other costs they face, including long lists of fees they pay companies that ship drugs from drug factories to hospitals.The current drug shortages have exposed the pressures on the generic market, and the scarcity of cancer treatments has put the spotlight on the troubled growth of Intas Pharmaceuticals in India. It produced two chemo therapies that Ms. Scanlan was to receive early on.Its market share for one of the drugs, methotrexate, which is also used in pediatric cancers and rheumatoid arthritis, grew to 35 percent last year from about 7 percent in 2018, according to the U.S. Pharmacopeia. The data shows the price per dose also fell, to $20 in 2022 from about $25 in 2018.Prices also fell during those years for carboplatin and cisplatin, which tumbled to $15 a dose. Intas’ market share grew, particularly for cisplatin, to 62 percent of the U.S. supply in 2022 from 24 percent in 2018.Ms. Scanlan’s husband, Joe Carr, left, helped wrap her amputated arm in the bathroom.Mark Wallheiser for The New York TimesNot ‘a first-world nation’Dr. Julie Gralow, chief medical officer of the American Society of Clinical Oncology, discovered signs of stockpiling in some health systems as early as February when the F.D.A. first announced the shortage, while shelves were empty at other health centers.“We’re calling it a maldistribution based on who has access — who can afford to create a little stockpile at their site,” Dr. Gralow said.By May her group and others relied on established tenets of bioethics to help cancer centers decide which patients should get scarce treatments, favoring patients with a shot at a cure over those staving off death. Dr. Gralow said researchers were beginning to study whether the chemo shortages are affecting patient survival. Results could take years.The emotional impact has varied widely. Some people with cancer were too focused on paying rent or feeding a family to fight for the medications they desperately needed, said Danielle Saff, a social worker with CancerCare, a nonprofit that supports patients.Others, like Lucia Buttaro, 60, a professor at Fordham University, were furious. She did not get her prescribed carboplatin for a reoccurrence of ovarian cancer in May or June, even though cancer was spreading in her lungs.“In my opinion, we don’t qualify as a first-world nation if you can’t get what you need,” she said.In the case of Ms. Scanlan in Florida, because her cancer was rare, invasive and advanced rapidly, it remains unclear whether the shortages played a role.Still, cancer experts expressed concerns that she had not received standard chemotherapy cocktail regimens before her amputation in September.Failure to use the three “modern miracle” generic chemotherapies for osteosarcoma patients “is a real problem,” said Dr. Lee Cranmer, a sarcoma expert at Fred Hutch Cancer Center in Seattle, who was not involved in Ms. Scanlan’s treatment.She has since received radiation. Last month, she learned the cancer already in her rib and spine had not spread further. Although her new care team at Moffitt Cancer Center in Tampa recently recommended palliative care, she said she felt defeated and terrified.The shortages took a toll, she said, adding: “I can’t help but think about what if something different happened from the beginning.” Ellen Gabler contributed reporting.

Lawmakers, U.S. officials and industry experts have offered measures to try to shore up the generic drug market.At several congressional hearings this year, ideas to fix drug shortages were as numerous as the number of scarce drugs.The rationing of key chemotherapies added urgency to the crisis.Two of these drugs, carboplatin and cisplatin, are inexpensive and are used to treat up to 20 percent of cancer patients, according to the National Institutes of Health.Momentum to shore up supplies of such crucial generic drugs grew this year after lawmakers returned from town hall meetings in their districts and reported on somber visits to their local hospitals. “People are dying because of this,” Representative Debbie Dingell, a Democrat of Michigan, said at one hearing.President Biden announced a plan in November to use his executive authority to expand federal authorities’ ability to invest in domestic manufacturing to ease some drug shortages, including those of morphine, insulin and flu vaccines. He also created a cabinet-level council focused on shortages and set aside $35 million to help prevent shortages of sterile injectable drugs like propofol or fentanyl, which are used in surgery.Here are some solutions that have been percolating:Set a price floor for lifesaving drugsA dozen executives in the generic industry said in interviews that their market was beset by unsustainably low prices, pushed down in part by intermediary companies. These middlemen compete for hospital clients, sometimes based on who can offer the lowest drug prices.Generic industry executives suggested setting a minimum price — sometimes referred to as a price floor — for generic drugs, particularly for the injectable ones that are most delicate to produce and are routinely in short supply.Marta Wosińska, a former economist for the Food and Drug Administration and deputy director for policy at the Duke-Margolis Center for Health Policy, has proposed a plan addressing prices that would reward drugmakers with the best record for quality and stability. “We’re paying too little for some of these drugs,” Dr. Wosińska said. “We need to be paying more for reliability, manufacturing quality. It’s not just about paying more.”Consider government manufacturingThe American Medical Association recently updated its policy on drug shortages, recommending that nonprofits or governments play a role in shoring up supplies, especially in the case of low-cost generic drugs that are challenging to make.The group, which represents thousands of doctors, urged the U.S. government to consider manufacturing some drugs, citing the examples of Sweden, Poland and India. In a related move, Senator Elizabeth Warren, a Democrat of Massachusetts, reintroduced a bill to create a federal drug manufacturing office that would oversee and encourage government production of certain medicines that are officially in shortage.Add transparency to the supply chainAbout a dozen people at the F.D.A. monitor and try to avert shortages. They also deal with ones they could not prevent. The agency has asked Congress to require drugmakers to report surges in demand. It also sought authority to require more information — like disclosure of the origins of basic ingredients — on the drug’s label.Encourage stockpilingSeveral groups have said the government could create incentives for hospitals or others in the supply chain to create a strategic reserve of key medications. The American Cancer Society said this month in a letter to congressional leadership that buffer stock would protect against catastrophes like a hurricane, a war or an unexpected event.But the group warned in the letter that the solution would be limited, “if the cause of a shortage is due to chronic unsustainable market conditions” that prompt companies to stop making drugs.Make more medicines in the U.S.The idea of reshoring — or bringing back drug manufacturing — and investing in existing domestic generic drugmaking facilities comes up routinely. Proponents note that relying heavily on other nations creates a national security vulnerability. An estimated 83 percent of the active ingredients in generic medicines are made overseas.Critics of the idea say domestic production is no panacea. They point to recent bankruptcies among generic drugmakers in the United States as well as the tornado that ripped through a Pfizer generic drug plant earlier this year.Propose more small-batch manufacturingLast winter, the Children’s Hospital Association, which represents 220 hospitals, anticipated a major supply disruption in albuterol treatments, which are given to children struggling to breathe. They turned to STAQ Pharma, an Ohio compounding pharmacy that makes custom batches of medications. The company ramped up production and helped ease the shortage. Such efforts are allowed only if a drug is on the official F.D.A. shortage list.The Association for Health System Pharmacists, a trade group, has proposed that the F.D.A. provide more information on the quality of such compounding pharmacies. Hospitals might otherwise hesitate to rely on them, given the history of problems at the New England Compounding Center, which was linked to 64 deaths after patients received tainted injections. The disaster led to criminal charges and civil settlements; the F.D.A. has since tightened requirements on such facilities.

The Latest NewsThe number of high school students who reported using e-cigarettes fell to 10 percent in the spring of this year from 14 percent last year, according to the results of an annual survey released on Thursday by federal health agencies.Vaping rose slightly among middle school students, to 4.6 percent this year from 3.3 percent in 2022. The use of traditional cigarettes among high school students remained at a record low of less than 2 percent.The decline in high school vaping rates was “encouraging,” said Linda Neff, an official with the Centers for Disease Control and Prevention and the lead author on the latest survey report. But she said the results for older teenagers were tempered by very small increases in middle school students reporting tobacco use.Puff Bar e-cigarettes.Jenna Schoenefeld for The New York TimesWhat’s Behind the Numbers: Flavor bans may have had an effect.One thing is clear about underage e-cigarette use: Adolescents like flavors. About 90 percent of the students who reported vaping said they used flavored products, citing favorites that tasted like fruit and candy.Teenagers identified Elf Bar and Esco Bar as their favorite brands, well-known for flavors such as strawberry kiwi and watermelon ice.Public health advocates in California recognized the allure, leading to a yearslong fight to pass a ban on flavored tobacco products, which took effect in December. It quickly led to falling sales, according to data from the C.D.C. Foundation. From December 2022 to June of this year, flavored e-cigarette sales fell by nearly 70 percent, to 179,000 from about 575,000 vapes or refills.The ban no doubt made it harder for young people to buy vapes in California, where you must be 21 to buy tobacco products.Public health experts also linked other state and local flavor bans and education campaigns to the falling high school vaping rate, which is the lowest in nearly a decade. And a few years ago, under public pressure, Juul, which had once been the most popular brand, withdrew most of its flavors from the market.The survey was given in about 180 schools nationwide, and was released by the C.D.C. and the Food and Drug Administration. It reported on e-cigarette use in the last 30 days but did not include any state-specific information.In all, about 2.1 million middle and high school students reported using e-cigarettes, down from 2.5 million last year. But surveys conducted during a few previous years since the peak of the vaping crisis in 2019 have carried notes of caution about drawing strict comparisons year-to-year because of pandemic conditions when students were in and out of school.Why It Matters: Studies identify health risks of vaping for teenagers.Federal officials who regulate e-cigarettes see their use as an aid in helping adult smokers quit traditional cigarettes, given the well-known cancer risks.But e-cigarette use has become wildly popular among nonsmokers. About 40 percent of people who use e-cigarettes are under 25, including many who started when Juul was first introduced. A majority of those young people never smoked before vaping, according to the C.D.C.The health effects are well known by now. One recent University of Southern California study noted the toxicity of the chemicals in e-cigarettes and sent questionnaires to adolescents who vaped. It found significant increases in wheezing, shortness of breath and bronchitis symptoms. And many experts have expressed concerns about the effect of nicotine addiction on the adolescent’s developing brain.What’s Next: A proposed menthol ban and heightened enforcement of illegal imports.The F.D.A. is moving toward a ban on menthol cigarettes and is advancing a proposal to drastically cut nicotine levels in cigarettes. That has led legacy tobacco companies to embrace e-cigarette sales as the way forward in the marketplace to offset overall declining cigarette sales.Yet those companies — along with many lawmakers in Congress and antismoking groups — say they have been dismayed with what they consider lax enforcement by the F.D.A. While the agency has authorized about two dozen vaping products for sale, thousands of illicit candy-colored flavored vapes have flooded the country and are top sellers.The F.D.A. said it would press ahead with its enforcement efforts, including its import ban on Elf Bar and Esco Bar products and fines on retailers who continue to sell them. The agency has issued warning letters to makers of those vapes and many others.Brian King, the F.D.A.’s tobacco division chief, welcomed the findings, but said: “We can’t rest on our laurels. There’s more work to be done to build on this progress.”Dr. Neff said her agency needed to better understand why there was a small but significant increase in middle school use of any tobacco product, to 6.6 percent this year from 4.5 percent last year.“Our work is far from done,” Dr. Neff said.Other researchers noted that the combined general use of tobacco products by middle and high school students barely fell, to 10 percent this year from 11 percent last year. “On balance, it’s no change in the overall youth tobacco use,” said Karen Knudsen, chief executive of the American Cancer Society. “And that’s concerning.”

The F.D.A. has approved many new programs that use artificial intelligence, but doctors are skeptical that the tools really improve care or are backed by solid research.In medicine, the cautionary tales about the unintended effects of artificial intelligence are already legendary.There was the program meant to predict when patients would develop sepsis, a deadly bloodstream infection, that triggered a litany of false alarms. Another, intended to improve follow-up care for the sickest patients, appeared to deepen troubling health disparities.Wary of such flaws, physicians have kept A.I. working on the sidelines: assisting as a scribe, as a casual second opinion and as a back-office organizer. But the field has gained investment and momentum for uses in medicine and beyond.Within the Food and Drug Administration, which plays a key role in approving new medical products, A.I. is a hot topic. It is helping to discover new drugs. It could pinpoint unexpected side effects. And it is even being discussed as an aid to staff who are overwhelmed with repetitive, rote tasks.Yet in one crucial way, the F.D.A.’s role has been subject to sharp criticism: how carefully it vets and describes the programs it approves to help doctors detect everything from tumors to blood clots to collapsed lungs.“We’re going to have a lot of choices. It’s exciting,” Dr. Jesse Ehrenfeld, president of the American Medical Association, a leading doctors’ lobbying group, said in an interview. “But if physicians are going to incorporate these things into their workflow, if they’re going to pay for them and if they’re going to use them — we’re going to have to have some confidence that these tools work.”From doctors’ offices to the White House and Congress, the rise of A.I. has elicited calls for heightened scrutiny. No single agency governs the entire landscape. Senator Chuck Schumer, Democrat of New York and the majority leader, summoned tech executives to Capitol Hill in September to discuss ways to nurture the field and also identify pitfalls.Google has already drawn attention from Congress with its pilot of a new chatbot for health workers. Called Med-PaLM 2, it is designed to answer medical questions, but has raised concerns about patient privacy and informed consent.Dr. Eric Topol is an optimist about A.I.’s potential in medicine. But, he cautioned, “you have to have really compelling, great data to change medical practice and to exude confidence that this is the way to go.”Kirsty O’Connor/PA Images, via AlamyHow the F.D.A. will oversee such “large language models,” or programs that mimic expert advisers, is just one area where the agency lags behind rapidly evolving advances in the A.I. field. Agency officials have only begun to talk about reviewing technology that would continue to “learn” as it processes thousands of diagnostic scans. And the agency’s existing rules encourage developers to focus on one problem at a time — like a heart murmur or a brain aneurysm — a contrast to A.I. tools used in Europe that scan for a range of problems.The agency’s reach is limited to products being approved for sale. It has no authority over programs that health systems build and use internally. Large health systems like Stanford, Mayo Clinic and Duke — as well as health insurers — can build their own A.I. tools that affect care and coverage decisions for thousands of patients with little to no direct government oversight.Still, doctors are raising more questions as they attempt to deploy the roughly 350 software tools that the F.D.A. has cleared to help detect clots, tumors or a hole in the lung. They have found few answers to basic questions: How was the program built? How many people was it tested on? Is it likely to identify something a typical doctor would miss?The lack of publicly available information, perhaps paradoxical in a realm replete with data, is causing doctors to hang back, wary that technology that sounds exciting can lead patients down a path to more biopsies, higher medical bills and toxic drugs without significantly improving care.Dr. Eric Topol, author of a book on A.I. in medicine, is a nearly unflappable optimist about the technology’s potential. But he said the F.D.A. had fumbled by allowing A.I. developers to keep their “secret sauce” under wraps and failing to require careful studies to assess any meaningful benefits.“You have to have really compelling, great data to change medical practice and to exude confidence that this is the way to go,” said Dr. Topol, executive vice president of Scripps Research in San Diego. Instead, he added, the F.D.A. has allowed “shortcuts.”Large studies are beginning to tell more of the story: One found the benefits of using A.I. to detect breast cancer and another highlighted flaws in an app meant to identify skin cancer, Dr. Topol said.Dr. Jeffrey Shuren, the chief of the F.D.A.’s medical device division, has acknowledged the need for continuing efforts to ensure that A.I. programs deliver on their promises after his division clears them. While drugs and some devices are tested on patients before approval, the same is not typically required of A.I. software programs.One new approach could be building labs where developers could access vast amounts of data and build or test A.I. programs, Dr. Shuren said during the National Organization for Rare Disorders conference on Oct. 16.“If we really want to assure that right balance, we’re going to have to change federal law, because the framework in place for us to use for these technologies is almost 50 years old,” Dr. Shuren said. “It really was not designed for A.I.”Other forces complicate efforts to adapt machine learning for major hospital and health networks. Software systems don’t talk to each other. No one agrees on who should pay for them.Dr. Nina Kottler, chief medical officer for clinical A.I. for Radiology Partners, has been leading a multiyear, multimillion-dollar effort to vet F.D.A.-cleared A.I. programs.Laylah Amatullah Barrayn for The New York TimesBy one estimate, about 30 percent of radiologists (a field in which A.I. has made deep inroads) are using A.I. technology. Simple tools that might sharpen an image are an easy sell. But higher-risk ones, like those selecting whose brain scans should be given priority, concern doctors if they do not know, for instance, whether the program was trained to catch the maladies of a 19-year-old versus a 90-year-old.Aware of such flaws, Dr. Nina Kottler is leading a multiyear, multimillion-dollar effort to vet A.I. programs. She is the chief medical officer for clinical A.I. at Radiology Partners, a Los Angeles-based practice that reads roughly 50 million scans annually for about 3,200 hospitals, free-standing emergency rooms and imaging centers in the United States.She knew diving into A.I. would be delicate with the practice’s 3,600 radiologists. After all, Geoffrey Hinton, known as the “godfather of A.I.,” roiled the profession in 2016 when he predicted that machine learning would replace radiologists altogether.Dr. Kottler said she began evaluating approved A.I. programs by quizzing their developers and then tested some to see which programs missed relatively obvious problems or pinpointed subtle ones.She rejected one approved program that did not detect lung abnormalities beyond the cases her radiologists found — and missed some obvious ones.Another program that scanned images of the head for aneurysms, a potentially life-threatening condition, proved impressive, she said. Though it flagged many false positives, it detected about 24 percent more cases than radiologists had identified. More people with an apparent brain aneurysm received follow-up care, including a 47-year-old with a bulging vessel in an unexpected corner of the brain.At the end of a telehealth appointment in August, Dr. Roy Fagan realized he was having trouble speaking to the patient. Suspecting a stroke, he hurried to a hospital in rural North Carolina for a CT scan.The image went to Greensboro Radiology, a Radiology Partners practice, where it set off an alert in a stroke-triage A.I. program. A radiologist didn’t have to sift through cases ahead of Dr. Fagan’s or click through more than 1,000 image slices; the one spotting the brain clot popped up immediately.The radiologist had Dr. Fagan transferred to a larger hospital that could rapidly remove the clot. He woke up feeling normal.“It doesn’t always work this well,” said Dr. Sriyesh Krishnan, of Greensboro Radiology, who is also director of innovation development at Radiology Partners. “But when it works this well, it’s life changing for these patients.”Dr. Fagan wanted to return to work the following Monday, but agreed to rest for a week. Impressed with the A.I. program, he said, “It’s a real advancement to have it here now.”Dr. Jesse Ehrenfeld, the American Medical Association president. “If physicians are going to incorporate these things into their workflow,” he said, “we’re going to have to have some confidence that these tools work.”David Kasnic for The New York TimesRadiology Partners has not published its findings in medical journals. Some researchers who have, though, highlighted less inspiring instances of the effects of A.I. in medicine.University of Michigan researchers examined a widely used A.I. tool in an electronic health-record system meant to predict which patients would develop sepsis. They found that the program fired off alerts on one in five patients — though only 12 percent went on to develop sepsis.Another program that analyzed health costs as a proxy to predict medical needs ended up depriving treatment to Black patients who were just as sick as white ones. The cost data turned out to be a bad stand-in for illness, a study in the journal Science found, since less money is typically spent on Black patients.Those programs were not vetted by the F.D.A. But given the uncertainties, doctors have turned to agency approval records for reassurance. They found little. One research team looking at A.I. programs for critically ill patients found evidence of real-world use “completely absent” or based on computer models. The University of Pennsylvania and University of Southern California team also discovered that some of the programs were approved based on their similarities to existing medical devices — including some that did not even use artificial intelligence.Another study of F.D.A.-cleared programs through 2021 found that of 118 A.I. tools, only one described the geographic and racial breakdown of the patients the program was trained on. The majority of the programs were tested on 500 or fewer cases — not enough, the study concluded, to justify deploying them widely.Dr. Keith Dreyer, a study author and chief data science officer at Massachusetts General Hospital, is now leading a project through the American College of Radiology to fill the gap of information. With the help of A.I. vendors that have been willing to share information, he and colleagues plan to publish an update on the agency-cleared programs.That way, for instance, doctors can look up how many pediatric cases a program was built to recognize to inform them of blind spots that could potentially affect care.James McKinney, an F.D.A. spokesman, said the agency’s staff members review thousands of pages before clearing A.I. programs, but acknowledged that software makers may write the publicly released summaries. Those are not “intended for the purpose of making purchasing decisions,” he said, adding that more detailed information is provided on product labels, which are not readily accessible to the public.Getting A.I. oversight right in medicine, a task that involves several agencies, is critical, said Dr. Ehrenfeld, the A.M.A. president. He said doctors have scrutinized the role of A.I. in deadly plane crashes to warn about the perils of automated safety systems overriding a pilot’s — or a doctor’s — judgment.He said the 737 Max plane crash inquiries had shown how pilots weren’t trained to override a safety system that contributed to the deadly collisions. He is concerned that doctors might encounter a similar use of A.I. running in the background of patient care that could prove harmful.“Just understanding that the A.I. is there should be an obvious place to start,” Dr. Ehrenfeld said. “But it’s not clear that that will always happen if we don’t have the right regulatory framework.”

R.J. Reynolds menthol e-cigarettes are top sellers with an estimated $1.6 billion in annual sales. The company vowed to fight the ruling in court.The Food and Drug Administration has ordered R.J. Reynolds to stop selling its popular Vuse Alto menthol e-cigarettes, a decision Reynolds immediately said it would challenge in court.On Thursday, the agency denied applications by Reynolds to keep its top-selling menthol products permanently on the market, saying that the company did not meet the federal standards that require the e-cigarettes to provide more of a health benefit than a risk. In the case of the Vuse vapes, the F.D.A. said the risks of attracting young people to the popular menthol and flavored products outweighed the potential for helping traditional smokers quit.The decision does not apply to the company’s tobacco-flavored products.Some public health experts have viewed the federal agency’s most recent rejections of menthol e-cigarettes as an indication that the agency is more strictly limiting menthol products. The F.D.A. is expected, perhaps by the end of this year, to move toward outlawing all menthol cigarettes, including Newports, a top seller for Reynolds with $7.5 billion in annual sales, according to Goldman Sachs research.British American Tobacco, the parent company of R.J. Reynolds, said in a statement that the F.D.A.’s latest ruling “flies in the face of proven science.” The company said it would fight the decision in court, which could allow Reynolds to keep the disputed Vuse products on the market indefinitely.Juul and other e-cigarette makers that are appealing similar agency decisions have been permitted to keep their vaping products on the shelves during litigation.If the F.D.A. were to succeed in court against Reynolds, the company would be dealt a severe financial blow. Market data analyzed by Goldman Sachs indicates that the menthol variety is the top seller of Vuse products, and those menthol vapes make up about 29 percent of the U.S. e-cigarette market, representing $1.6 billion in sales. Overall, Vuse products, including tobacco-flavored products, comprise 40 percent of the market.The F.D.A. has had the authority to determine the sale of e-cigarettes since 2016. It has denied millions of applications either for products to stay on the market or for the sale of new vaping devices. The agency has pledged to decide every application by the end of this year.Antismoking groups and others have urged the F.D.A. to more tightly regulate the e-cigarette market, and noted that a recent survey of middle and high school students showed that Vuse vapes were a popular choice among those who used e-cigarettes.Reynolds has tried to position its products to regulators as legitimate alternatives for adults in an e-cigarette space flooded with illicit products. The company volunteered to stop selling its mixed berry flavor, which was also denied marketing authorization by the F.D.A. on Thursday.“Central to the efficacy of any regulated market is the rule of law — where good behavior is encouraged, and bad behavior punished,” Kingsley Wheaton, a British American Tobacco executive, said in the company’s statement. “We also remain deeply concerned that the F.D.A. continues to allow the proliferation of youth-appealing vapor products like Cotton Candy and Peanut Butter Cookie, which are flooding U.S. retail shelves. Companies in open defiance of the agency must be held accountable.”But Reynolds is contesting other restrictions. It has filed suit in California against the state’s new ban on flavored tobacco, after the state attorney general warned the company and another about marketing products that were said to have a “cooling” flavor.Yolonda Richardson, president of the Campaign for Tobacco-Free Kids, applauded the F.D.A.’s decision on Vuse, saying it was “one of the strongest actions the F.D.A. has taken to rid the market of illegal, flavored e-cigarettes and is a necessary step toward ending the youth e-cigarette crisis in the United States.”Alex Liber, a Georgetown University assistant professor and tobacco control policy researcher, recently worked on a paper linking flavored-vape bans to an increase in cigarette sales.He said the F.D.A. appeared to be on a path of authorizing only vapes that taste like a cigarette. The agency has rejected other menthol e-cigarette applications, deeming them too alluring to adolescents to outweigh the benefit to adults.“Whatever that bar and evidence is, I don’t think anyone has hit it,” Dr. Liber said. “I don’t know if F.D.A. knows what it looks like. I don’t know what that would be.”

Some vapes are appearing with increasing nicotine levels that approach those in a carton of cigarettes. U.S. regulators did not authorize them, but have failed to keep them off shelves.Juul was once the cool vape, blamed for hooking teenagers on e-cigarettes, and it is set to pay billions of dollars in legal settlements.Then came Puff Bar, which was hot in high schools until federal officials began impounding those vapes. Elf Bar stepped in, and its products have been seized at the border. A parade of facsimiles is moving in right behind them: Virtue Bar, Juicy Bar, Lost Mary, Lost Vape and many more.The latest flood of illicit e-cigarettes is arriving from China in Barbiecore colors and fruit, ice cream and slushy flavors, and accounts for a major share of the estimated $5.5 billion e-cigarette market in the United States.The never-ending influx of vapes, some offering 5,000 or more puffs per device or escalating nicotine levels, has exposed a gaping lapse in enforcement by the Food and Drug Administration, which has authorized only a handful of the hundreds of options that line convenience store walls nationwide. Members of Congress, two dozen state attorneys general and even the Big Tobacco companies have stepped up their calls for the agency to get the situation under control.Granted, the latest pleas by the tobacco industry are viewed by antismoking groups as a cringe-worthy effort to lock down market share, but some others interpret the addition of these odd bedfellows as a sign of a market run amok.The F.D.A. “has been dealt a very difficult hand, and a lot of which includes putting the genie back — or stuffing the genie back — in the bottle,” said Erika Sward, assistant vice president of advocacy for the American Lung Association. “And I don’t envy them for that.”Agency officials said they had used every tool within their authority to crack down on e-cigarette outlaws. Yet recent fines issued by the agency topped out at about $19,000 per violation and largely targeted a few products sold at each store. The agency’s orders telling six manufacturers to stop selling certain products were directed at U.S. stores, some of which were in small cities.And though the F.D.A. has fired off hundreds of warning letters, the effect is barely felt: Flavored vape sales have surged 60 percent over the past three years, to 18 million vaping products a month in June from 11 million a month in early 2020, according to the C.D.C. Foundation.“The F.D.A. should not be having any of these flavored e-cigarettes on the market,” said Yolonda Richardson, president of the Campaign for Tobacco-Free Kids. “And so it just needs to do its job.”When the F.D.A. received expanded authority to regulate e-cigarettes in 2016, the objective was to draw a new line in public health: Smokers would have an alternative to traditional cigarettes, and tobacco use among minors would remain at historic lows.Seven years on, nearly 40 percent of e-cigarette users are 25 or younger, according to the Centers for Disease Control and Prevention. And of the 2,000 or so vaping and e-cigarette products on the market, the agency has only given the green light to about two dozen of them, and it still has to deal with a backlog of applications, according to research on the industry.There are few places where the problem feels more pressing than in high school bathrooms, where students crowd the stalls between classes to get a nicotine fix.Kyle Wimmer, an art teacher at Mountain Range High School in Westminster, Colo., helps students quit vaping through creating artwork out of relinquished vape pens.Kevin Mohatt for The New York TimesTeenage vaping rates have fallen roughly by half since their height during the Juul craze of 2019, to about 14 percent of high school students last year from nearly 28 percent at their peak, federal surveys show. Those rates were based on survey responses in which students said whether they had vaped within the past 30 days.Kyle Wimmer, an art teacher at Mountain Range High School, north of Denver, frequently hears from students dealing with nicotine addiction from e-cigarette use.He accepts discarded vapes and helps young people turn them into art. And as a teacher who has been open about his past struggles with alcohol, he’s also there to listen.“It’s hard to tell kids not to do this when they’re hooked because they can’t just stop,” Mr. Wimmer said, adding: “They’re having troubles. They’re struggling.”A vape-inspired piece at Mountain Range High School. “It’s hard to tell kids not to do this when they’re hooked because they can’t just stop,” Mr. Wimmer said.Kevin Mohatt for The New York TimesA growing body of research shows that while vapes may not be as toxic as cigarettes, they are far from healthy, particularly for adolescents who become addicted to nicotine while their brains are still developing.The American Heart Association has raised the alarm about possible cardiovascular effects from e-cigarettes and called for more research. One recent meta-analysis reported higher heart attack risks in e-cigarette users than in those who did not vape or smoke anything. (Cigarette smokers had the highest risk.)In recent years, the market has begun to move toward high-volume vapes advertising 5,000 to 6,000 puffs — with about as much addictive nicotine as is in a carton of cigarettes. The devices come in flavors that could appeal to younger adolescents such as birthday shake, gummy bear and watermelon ice, and they have higher concentrations of nicotine than were found before. The prices have also dropped, said Barbara Schillo, chief research officer for the Truth Initiative, who documented the trend in a recent study.“In other words, these disposable devices are getting bigger, stronger and cheaper,” Dr. Schillo said.Calls for change have only grown louder. In a letter sent in late August, 30 state attorneys general urged the F.D.A. to do more to deter youth vaping and to ban all but tobacco flavored e-cigarettes.Lawmakers, including Senator Richard J. Durbin, Democrat of Illinois and a leading opponent of e-cigarettes, have pushed for action. His office discovered nearly two dozen types of vapes being sold online even after the F.D.A. had denied their marketing applications and sent them warning letters.“I just don’t understand it,” Senator Durbin said in a floor speech last month, adding that the F.D.A. “is cowardly, refusing to use its full arsenal of enforcement tools — fines, injunctions — for even these most flagrant cases.”Even R.J. Reynolds, the maker of Newport and Camel cigarettes and the best-selling Vuse vapes, has invoked public health in a petition lodged with the F.D.A. seeking official action. It asked the agency to prioritize enforcement of flavored, disposable vapes.Luis Pinto, a spokesman for the company, said that devices aimed at young people and minors threatened the efforts of Reynolds and others to convert adult smokers to e-cigarette users. “The whole category is in peril,” he said.Reynolds’s Vuse e-cigarettes led vaping sales for a year ending in August, Goldman Sachs data shows, with $2.2 billion in sales. The “other” category, which included flavored imports, trailed with $1.6 billion in sales, with Juul close behind.Brian King, the F.D.A.’s tobacco center chief, said that the agency had ramped up warnings, fines and injunctions on illicit vape makers, sellers and distributors. He rebutted some of the criticism from “the cheap seats” and said enforcement efforts needed to be strategic and methodical.“It’s a very complex chess match, not a game of tic-tac-toe,” Dr. King said. “And we need to ensure that the actions we take are both scientifically and legally defensible.”The F.D.A. has been working with border authorities to seize imports of Elf Bar and Esco Bar products from China.Andrew Harnik/Associated PressF.D.A. officials meet regularly with Justice Department prosecutors, Dr. King said, describing them as critical partners. The agency has also worked with border authorities to seize imports of Elf Bar and Esco Bar products, he added. In addition, the agency has received funding to begin an effort to closely track the rapidly morphing vape marketplace.“Nothing’s off the table when it comes to enforcement,” he said.In late September, the F.D.A. announced 22 fines of $19,192 each against gas stations that received warning letters but did not stop selling Elf Bar products.The F.D.A. has required e-cigarette makers to file applications to sell their products and to submit proof that the products would be likely to compel cigarette smokers to switch — but not to attract new users. The agency has denied millions of applications and let some top-selling products remain on market pending decisions.Two years have passed since a court-imposed deadline required the F.D.A. to respond to all applications. Dr. King said it would finalize decisions, including on some Vuse and Juul vapes, by the year’s end.The lengthy, opaque approval process, marked with legal challenges and defiance of the F.D.A.’s decrees, has opened the door to the shape-shifting influx of unauthorized vapes that come by air, land and sea from factories in China (where flavored vapes are outlawed).The confusing mix of product statuses has prompted the Energy Marketers of America, an organization representing retailers, including convenience stores linked to gas stations, to file a petition with the F.D.A. seeking clarity about which e-cigarettes the stores can legally sell.Stores are “well positioned to aid in the fight against illegal and dangerous products by keeping them off their shelves,” according to the petition.

Genetic testing that reveals potential cancer risks or other maladies with no regulatory oversight is among the targets of the agency’s proposed review.The Food and Drug Administration said on Friday that it was moving to close what has widely been viewed as a loophole allowing certain lab tests — like those that determine the profile of a tumor or the genetic health of a fetus — to bypass review with virtually no tracking or oversight.The agency proposed a rule that would bring the tests under its regulatory authority, requiring laboratories conducting them to provide data on test accuracy. Hundreds of tests on the market have very little oversight and may be misleading to the public and patients seeking to learn whether they have Lyme disease, Alzheimer’s or will develop cancer.The proliferation of these tests “leaves Americans vulnerable to making important health care choices based on potentially faulty or inaccurate test results,” Dr. Robert Califf, the F.D.A. commissioner, said in a news briefing on Friday.The tests, which included the first ones to detect Covid-19, have been subject to agency concern for 30 years and have been a perennial — yet essentially untouchable — target by lawmakers dating back to former Senators Edward Kennedy and Barack Obama and as recently as this year.Academic medical centers that include labs operating the tests have opposed changes, citing the importance of being nimble in the face of a rapidly changing, pandemic-prone world.Though renewed attention about the tests’ accuracy may be unsettling to patients, there have been few clues available to them — or even to their doctors — about whether the tests were vetted or received thorough F.D.A. oversight, according to Jeff Allen, president of the Friends of Cancer Research, a nonprofit partly funded by pharmaceutical companies.“A rule like this is getting to it at the front end to be sure each test out there meets reliable accuracy standards — so those questions don’t need to be asked,” he said.Mr. Allen said the pathology lab in a hospital may know the origins of a test, but that information is rarely passed on to doctors and patients. He said that his organization was concerned about the accuracy of tests administered to glean the genetic profile of a tumor that led to decisions on treatment.An investigation by The New York Times found that prenatal genetic screening tests were frequently wrong, with many false-positive results.Academic researchers, physicians and the F.D.A. have criticized other, similar tests, as well. Those include tests that are meant to calculate a person’s so-called genetic propensity for developing diabetes or becoming an elite athlete.Doctors have also raised concerns about tests meant to predict the chances of developing Alzheimer’s disease. In 2015, the F.D.A. issued a report about 20 tests of concern, including one to detect ovarian cancer and another for Lyme disease. A longstanding concern about the tests is whether they have misled patients facing decisions about aborting a fetus with a possible genetic abnormality or getting a mastectomy or hysterectomy based on cancer screenings.Opponents of additional F.D.A. oversight say the agency does not have the resources to review and oversee tests for emerging health concerns.Susan Van Meter, president of the American Clinical Laboratory Association, which represents lab companies and test makers, said in a statement that billions of tests were run each year that influence a majority of the decisions made by health providers.The association noted that the only test now available to detect fentanyl mixed with a dangerous animal tranquilizer, xylazine — a combination known as “tranq dope” — is one that would be subject to the new layer of oversight.“F.D.A. seriously risks falling behind on its current public health priorities,” according to the association’s statement released on Friday. The association said it planned to ask the agency to withdraw the proposed rule and said it would continue to work with Congress on the matter.An effort to update oversight of lab tests failed late last year in Congress after advocacy groups spent countless hours on a compromise. Called the Valid Act, the measure was expected to pass in an omnibus budget bill, but ultimately was not included. It was reintroduced earlier this year.The regulatory paths for lab tests generally depend on who is analyzing the test. Tests manufactured by a company and performed by a consumer or health care provider tend to be regulated by the F.D.A., which requires the test maker to evaluate and report on its accuracy.The less regulated tests, known as “lab-developed” tests, tend to be processed at a central location with results transmitted back to consumers or health care providers. Those tests may be overseen by lab experts for Medicare and may also be accredited by the College of American Pathologists.The F.D.A. is not even sure how many lab-developed tests exist.“No one truly knows how many of these tests are out there, or who makes which one, let alone which tests have a track record of inadequate results and problems and which don’t,” said Dr. Jeffrey Shuren, the head of the F.D.A.’s medical device and diagnostics division, during the briefing on Friday.The proposed rule will be open for public comment and likely will be challenged in court, said Jeffrey Shapiro, a lawyer at King & Spalding who represents some labs that have developed tests.He said the lab-developed tests are services or procedures that are already regulated by Medicare officials.“This proposed rule is nothing new, it’s the same dispute that F.D.A. has been having with industry for 30 years,” Mr. Shapiro said. “Major economic questions like this one affecting the health of millions should be decided by Congress, not F.D.A.”The agency also noted how long the debate over these unregulated tests has dragged on, with Dr. Califf acknowledging on Friday that the agency had to deal with how prolific the tests had become.“Laboratory-developed tests play a central role in U.S. health care, and many are similar to other tests that come in to the F.D.A. for review,” Dr. Califf said. “This approach no longer makes sense and puts U.S. patients at risk.”